PSI - Issue 39

Raffaele Sepe et al. / Procedia Structural Integrity 39 (2022) 546–551 R. Sepe / Structural Integrity Procedia 00 (2021) 000–000

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4. Conclusions Aluminum-lithium alloys deliver numerous benefits for applications in which weight represents a key concern, thanks to their reduced mass density and enhanced mechanical properties compared to more traditional aluminum alloys. This document reports the first results of an experimental campaign on the fracture anisotropy for the third generation aluminum-lithium alloy Al-Li 2198-T851. Fatigue crack-growth tests were carried out on M(T) specimens with a initial central notch having different angles (30°, 45° and 60°) with the normal to the loading axis, in such a way to highlight the anisotropic characteristics of the material. Specimens were manufactured longitudinally ( L ) and transversally ( T ) with respect to the rolling direction of the sheets. Although the high inclinations of the central notch were aimed at driving the propagation toward the loading direction, all cracks propagated perpendicularly to the loading axis irrespective of the notch angle. Large scatter of the crack paths was observed for ( L ) specimens, due to a significant through-the-thickness anisotropy. On the other hand, ( T ) specimens presented crack paths almost perpendicular to the loading axis, suggesting that cracks propagated perpendicular to the loading axis but also tended to propagate between the grains of the material. Further studies on this line of research are intended to be notably developed. References Alexopoulos, N.D., Migklis, E., Stylianos, A., Myriounis, D.P., 2013. Fatigue behavior of the aeronautical Al–Li (2198) aluminum alloy under constant amplitude loading. International Journal of Fatigue, 56 95-105. Astarita, A., Squillace, A., Scala, A., Prisco, A., 2012. On the critical technological issues of friction stir welding T-joints of dissimilar aluminum alloys. J Mater Eng Perf 21 1763-1771. ASTM E647-15e1, Standard Test Method for Measurement of Fatigue Crack Growth Rates, ASTM International, West Conshohocken, PA, 2015. Bitondo, C., Prisco, U., Squillace, A., Giorleo, G., Buonadonna, P., Dionoro, G., et al., 2010. Friction stir welding of AA2198-T3 butt joints for aeronautical applications. Int J Mater Form 3 1079-1082. Cavaliere, P., Cabibbo, M., Panella, F., Squillace, A., 2009. 2198 Al–Li plates joined by friction stir welding: mechanical and microstructural behavior. Mater Des 30 3622-3631. Citarella, R., Giannella, V., 2021. Additive Manufacturing in Industry. Appl. Sci., 11 840. De, P.S., Mishra, R.S., Baumann, J.A., 2011. Characterization of high cycle fatigue behavior of a new generation aluminum lithium alloy. Acta Materialia, 59(15) 5946-5960. Heinz, A., Haszler, A., Keidel, C., Moldenhauer, S., Benedictus, R., Miller, W.S., 2000. Recent development in aluminium alloys for aerospace applications. Mater Sci Eng A, A280 102-107. Lavernia, E.J., Grant, N.J., 1987. Aluminium–lithium alloys. J Mater Sci 22 1521-1529. Rioja, R.J., Liu, J., 2012. Evolution of Al–Li base products for aerospace and space applications. Metall Mater Trans A, 43A 3325-3337. Steuwer, A., Dumont, M., Altenkirch, J., Birosca, S., Deschamps, A., Prangnell, P.B., et al., 2011. A combined approach to microstructure mapping of an Al–Li AA2199 friction stir weld. Acta Mater 59 3002-3011.